What should the president do if a “dirty” radioactive bomb were exploded in an American city? Should he or she support the construction of pebble-bed nuclear reactors to provide safe, clean energy? In this presidential primer, MacArthur fellow and UC-Berkeley physicist Muller ranges from terrorism to space exploration to global warming, offering basic information and countering myths. He says, for instance, that dirty bombs aren't as dangerous as people fear; if the radiation is diffused over a large area, the risk of death or of cancer is extremely low. In a survey of energy sources, Muller argues that much-hyped hydrogen and solar energy have a long way to go, whereas nuclear power and coal don't deserve the bad rap they receive. Regarding space exploration, Muller joins the ranks of scientists who maintain that it is better done by robots than by humans. Nuclear technology receives considerable attention, though information is repeated from one chapter to another, but an extensive, balanced section on global warming should be required reading for all informed citizens as well as Hillary Clinton, Barack Obama and John McCain. 50 illus. (July)